Transformer is a common magnetic component used in electric equipments which utilizes the electromagnetic induction to regulate the output voltage to range in a suitable scope for the electric equipment.
Please refer to FIG. 1, which is a schematic view showing the structure of a conventional transformer. As shown in FIG. 1, the transformer 1 includes a bobbin 10 which is wound by a primary winding and a secondary winding (not shown), and the primary and secondary windings are wrapped in an insulation tape 12, wherein a first output terminal 131 of the primary winding is wound on a pin 101 extended from the bobbin 10, and a second output terminal 141 of the secondary winding is a flying lead having a sleeve 142 attached thereto. Further, the transformer 1 also includes a magnetic core set 11 assembled with the bobbin 10, which has wound by the primary and secondary windings. Then, the outer surface of the magnetic core set 11 is further wrapped in several layers of insulation tape 12, to conform the transformer 1 to the safety regulation. Finally, the transformer 1 is electrically connected to a circuit board (not shown) through the pin 101 and the second output terminal 141 of the secondary winding.
However, the structure of the conventional transformer has some disadvantages. First, the wrapping of the insulation tape 12 as fabricating the conventional transformer 1 will cost a lot of time, and further, the wrapping also make the transformer 1 to occupy more space and have an uncontrolled appearance, so that when the transformer 1 is mounted on the circuit board (not shown), the layout of the circuit board might be influenced. For example, the folded corner 121 of the insulation tape 12 formed along the transformer 1 might press the adjacent electronic components, or the increased volume of the transformer 1 might contact with other electronic components on the circuit board. Furthermore, since the first output terminal 131 of the primary winding on the transformer 1 has to be wound on the pin 101, it might cause a difficulty in cable management, and also, the winding of the first output terminal 131 might occupy too much space so as to have an inappropriate contact with other pins or adjacent electronic components, thereby causing a short circuit. Besides, the first output terminal 131 of each primary winding is additionally attached by a sleeve 132 for preventing an overlapping therebetween, and also for avoiding a burn damage to the insulation layer of the primary winding as welding the first output terminal 131 on the pin 101. But, the attachment of the sleeve 132 to the first output terminal 131 one by one involves complicated steps which also increase the manufacturing cost. In addition, since the second output terminal 141 of the secondary winding is a flying lead, when the transformer 1 is mounted on the circuit board (not shown), it is uneasy to position and plug the flying lead in the preset via hole on the circuit board.
Therefore, how to develop a transformer with an insulation base so as to solve the drawbacks in the prior art is really an urgent demand.